Greetings,
QUOTE> Anyone selling Ceramic beads as insulation is selling snake oil, there is no insulation value!
ANS: Then some one sure screwed NASA. Maybe you can use your superior knowledge and expertise to help them get their money back. Which brings up another question, if ceramic beads are useless, how did the shuttle crafts manage to get back to earth without burning up? I await your ans.
Reply to the article you referred to:
QUOTE> for example, an assembly made up of a radiant barrier and an air space — to slow heat transfer.
Slow heat transfer? This person is relating to radiant energy as if it had mass, it doesn’t. BAD START. Also this energy is infrared energy and is usually referred to as short wave, as what is emitted by the sun and long wave which is what we are concerned with on earth.
This energy moves at about the speed of light. What’s slow about that? REALLY BAD START.
It has been my experience that people who want to spread dis-info and mis-info about RB use these tactics. There is more of this to come.
QUOTE>The sale and distribution of radiant barriers has always attracted a disproportionate share of scam artists, many of whom promise impossible energy savings.
ANS> Unfortunately, true. But then ALL FG and CEL sales people have to lie by direct lies or lies of omission every sale they make. IT starts with the phoney “R” factors advertized by the manufacturer, based on tests that DO NOT reflect your installed conditions, AND, THE GOV SUPPORTS THESE LIES. So what is disproportionate, and compared to what? More deliberate vagueness to confuse the issue.
QUOTE> The explanations made by these hucksters usually include multiple references to space vehicles and NASA.
ANS: Noticeable lack of specificity. AGAIN.
QUOTE> Having been swayed by this type of misinformation, a few builders have adopted an almost religious belief in the magical powers of radiant barriers.
ANS: Must be a lot of dumb builders out there. After all RB have been manufactured and installed in US for at 86 years that I know of. If they were so useless you would think that they would have gone the way of the dinosaur. God only knows how many architects and engineers have specified it during that time.
Nothing magical, pure science. More distracting meaningless comments. WHY?
QUOTE> A radiant barrier is a thin sheet of reflective material, often aluminum, applied to a substrate such as kraft paper, plastic film, cardboard, or plywood. By definition, a radiant barrier has a low emissivity (0.1 or less). Radiant barriers reduce radiant heat transfer across the space which they face. The lower a material’s emissivity, the more effective it is at reducing radiant heat transfer.
ANS: All true, BUT, the emissivity is not mentioned, which is, 97%. By the way look up the emissivity of the base material of you favorite insulation and get a shock Why wasn’t the emissivity mentioned?
QUOTE>Although radiant barriers can be made from a variety of materials, there is no such thing as radiant barrier paint. No one has yet invented a paint that achieves an emissivity of 0.1 or below.
ANS: True, and I challenged those products when they first came out. How ever, ceramic beads, as used by NASA, are a different story. Why wasn’t that mentioned? Doesn’t anyone proof read this guy?
QUOTE> Radiant barriers that aren’t facing an air space don’t work. If it’s sandwiched between a layer of sand and a concrete slab, it’s a conductor, not an insulator.
ANS: True, and true for any other materials. That should be obvious.
QUOTE> Although a radiant barrier has no R-value, it can help boost the R-value of an adjacent air space. According to ASHRAE Fundamentals, a vertical 3/4-inch air space has an R-value of about R-1 — assuming that the heat-emitting surface adjacent to the air space has an emissivity of 0.82. If the same air space is faced with a radiant barrier with a emissivity of 0.05, the R-value of the air space is boosted from R-1 to about R-3.
ANS: More distraction. Who cares what the “R” value of the space is if you’re reflecting 97% of the energy. This kind of analogy is to distract you BACK TO :R: factors.
QUOTE> The effect of a radiant barrier on a building assembly's R-value may be significant or insignificant, depending on whether the assembly is well insulated or poorly insulated. Radiant barriers do not significantly benefit well-insulated assemblies.
ANS: By whose definition of well insulated. If FG and CEL then I have to guess he’s ignoring the, up to, 72% increase in heat flow due to CONDENSATION. And foam has it’s problems too.
QUOTE> For example, consider drywall installed on a SIP wall. If the SIP has an R-value of R-30, the emissivity of the drywall hardly matters. Since the drywall is at room temperature, it's at thermal equilibrium with the other objects in the room, so radiant heat transfer isn’t a significant heat-transfer mechanism for people or objects in the room. (Radiant heat transfer only becomes significant when a radiating surface is at a significantly higher temperature than surfaces in the room or air space which it faces.)
ANS: Hardly matters? Give me a break. I would like to see install condition tests on that one. Prove the temp is at room temp. According to him this structure is 100% effective in stopping heat flow.
The rest is true reasonable true. But what is significant? Besides there are other problems with sips. I know, I have one.
QUOTE> Because building codes require the walls and ceilings of new homes to be insulated, there isn’t any need to install a radiant barrier in a well-designed home.
ANS: I beg to differ.
QUOTE> A few “religious believers” in radiant barriers have experimented with building wall or ceiling assemblies consisting of multiple 1-inch air spaces separated by aluminum foil. While these assemblies work — after all, if you put together a thick enough pile of R-3 pancakes, you can eventually achieve a reasonable R-value — they cost far more to build than ordinary walls with conventional insulation.
ANS: Back to switching you to R: factors. Notice how subtle he is.
If your reflecting 97% of the energy then you only need ONE. However there are other things to consider so I recommend Two foils. For maximum results I also recommend one layer over the interior studs, like a VB., with ½””Z” strips horizontal across the face of the studs, then dry wall. This calculates out to about 2 btu/sq ft/hr. Since this installation does not cause condensation there is not loss in performance. This can be used for ceilings too, only using ¾” thk furring strips instead of “Z” strips.
A two layer sys will cost less than conventional and the upgrade the same or slightly more.
QUOTE> Radiant barrier fanatics have also experimented with horizontal radiant barriers on the top side of attic floor insulation. There are two problems with such radiant barriers:
• Once the radiant barrier gets dusty, it’s no longer a low-e surface. Radiant barriers have to stay shiny to work.
• Unless the radiant barrier is perforated, it acts as a vapor barrier. During the winter, condensation will form on the underside of the radiant barrier.
ANS: He is using the label “FANATIC” to prejudice your mind. Why do you think ghe has to resort to this? And the process is more than experimental. I’ve been doing it for over 30 yrs. More deception.
RB DO NOT have to be shiny. More mis info. Infra use to laminate with the dull side facing out. Tested out and worked just fine for millions of sq ft. Heavy dust can reduce effectiveness up to about 20% according to the info I had. But one thing that is not mentioned is that the other foil side, facing down is unaffected and, IF there is a slight increase in the foil, it is still emitting only .03 %. So what are taking about, maybe one btu/hr/sq ft?
In the second point you have to remember that there is no condensation in multi layer wall and above drywall ceiling ass’y so using perforated RB to allow excess VAPOR out is perfectly acceptable.
Here he is referring to a RB in the attic attached to the rafters. I have never seen this in my area, ST Louis, but It could happen in certain areas of the country. I would think a RB installer would recommend the proper installation. Rafter installation is not the best as shown by the Florida tests. Installation of a one or two layer RB over the existing insulation is the preferable way to install. RB MUST be perforated, and seams NOT sealed/taped and is much more efficient.
This is the method I have used for 30 years.
Knowing the mechanics of how foil works will help you understand if there is a potential moisture problem.
When the heat energy radiates to the foil the foil’s temp will become the same as the room temp, AS WILL the air temp. Since the foil, air and dry wall are the same it cannot condensate moisture. HOWEVER if the foil temp can be dropped then you could get condensation. But then you should be looking for the source of the problem. Multi layer foil will not condensate because the extra foil, which are at the OUTSIDE temp protect the inner foil. I hope that’s clear. Now why didn’t he mention this?
QUOTE> Don’t be tempted to install foil-faced bubble pack under a concrete slab. The R-value of foil-faced bubble pack — generally between R-1 and R-2 — is far too low for such an application.
ANS: Unfortunately true. This was a hoped for app that didn’t work out. And it wasn’t foil faced as the concrete would destroy the reflectivity. The foil was BETWEEN two bubble foils.
QUOTE> Radiant-barrier roof sheathing only makes sense in hot-climate homes that have HVAC equipment or ductwork installed in an unconditioned attic.
ANS: AGAIN, not true.. Reducing the amount of RE to the insulation will help, but as the Florida tests showed, about 11%. But, 11% is 11% and you can’t get that by adding more bulk insulation to existing insulation, such as 6" added to 6".
The attic does not have to be conditioned. The equipment can be RB wrapped. Been there, done that. Still the sheathing foil is a good idea IF you’re using bulk insulation
QUOTE> . Here’s the logic: the builder knows that the HVAC equipment and ductwork will get very hot in the summer. The builder doesn’t want to move the HVAC equipment and ductwork where they belong — inside the home’s conditioned space — because it’s cheaper to install everything in the hot attic. So the builder installs radiant-barrier sheathing to keep the attic a little cooler. At best, it’s a halfway solution to a basic design problem.
ANS: True. Too bad the contractor wasn’t more familiar with the various apps of RB.
QUOTE> New homes in a cold climate, on the other hand, shouldn't use radiant-barrier roof sheathing. Up north, a sun-warmed attic helps lower heating bills.
ANS: Maybe, not cast in stone. However if the ceiling has multi layer foil you wouldn’t need sheathing RB.
QUOTE> According to a research report published by Oak Ridge National Laboratory, “The tests to date have shown that in attics with R-19 insulation, radiant barriers can reduce summer ceiling heat gains by about 16 to 42 percent compared to an attic with the same insulation level and no radiant barrier. These figures are for the average reduction in heat flow through the insulation path. They do not include effects of heat flow through the framing members. …
ANS: My experience has been about 30 to 40%. Plus, you have a significant increase in comfort.
If the RB is covering the framing members, how can it not affect the framing? Are joists magical? I have to assume from this description that the RB was over the insulation only. DUMB. But this would be typical of a gov run lab since they try to discredit RB. Remember, the gov wants you to use as much energy as possible as they make 10s of billions in energy taxes. God bless the USA, Inc.
QUOTE> Since the ceiling heat gains represent about 15 to 25 percent of the total cooling load on the house, a radiant barrier would be expected to reduce the space cooling portion of summer utility bills by less than 15 to 25 percent. Multiplying this percentage (15 to 25
ANS: 15 =25 %? What world are you living on. Since we’re talking about retrofit we can assume that we are talking about mostly FG insulated ceilings.
On a 95 deg. Day, uninsulated roof the ceil’g drywall temp can easily reach 110 degs. I know. I’ve checked some. Why do you think ACs run all day, constantly and do not turn off until about 10 PM or latter. With a floor temp of 75 deg that is 35 btu/sq ft/hr radiating into the house. By putting the RB over the existing insulation the AC run time will be reduce by at least 50%, providing there are no other excessive heat gaining problems, So tell me, how isn’t that significant?
QUOTE> If you live in a cold climate, radiant barriers make even less sense than they do in Florida. According to the U.S. Department of Energy’s Energy Efficiency and Renewable Energy Clearinghouse, “Two field tests, one in Minnesota and one in Canada, both found that a radiant barrier placed over R-19 attic floor insulation (which is less than half the DOE minimum recommendation for those climates), found that the radiant barrier contributed to less than a 1% reduction in energy consumption for heating and cooling.”
As with the Florida example, it should be pointed out that even these meager savings are associated with attics that are poorly insulated. If the attic has code-minimum insulation, the savings disappear.
If you live in a cold climate, radiant barriers make even less sense than they do in Florida. According to the U.S. Department of Energy’s Energy Efficiency and Renewable Energy Clearinghouse, “Two field tests, one in Minnesota and one in Canada, both found that a radiant barrier placed over R-19 attic floor insulation (which is less than half the DOE minimum recommendation for those climates), found that the radiant barrier contributed to less than a 1% reduction in energy consumption for heating and cooling.”
As with the Florida example, it should be pointed out that even these meager savings are associated with attics that are poorly insulated. If the attic has code-minimum insulation, the savings disappear.
ANS: I sure would like to know how they pulled that one off. In 1964 the Navy CBs switched from FG to RB in their ice cube forming walls. According to the fellow that was involved with the sw they saved about 30% on oil usage. So how did Minn come up with 1%? Very interesting.
QUOTE> In 2001, researchers from the National Association of Home Builders (NAHB) Research Center evaluated several energy-retrofit measures in a 1,270-square-foot ranch house in Henderson, Nevada. The researchers focused on measures appropriate for hot climates.
ANS: The results would be the same as Fl because they used the same method.
WHY didn’t they install over the insulation? Because they would have gotten better results.
Referring back to these claims that added bulk insulation is so effective, consider this: Adding 6” FG or cel to an existing 6” only increases the effectiveness, not savings, by about 7.5%. You’re saying 7.5 % is going to save at least 11% on the energy usage? In your fondest dreams.
Any more articles for me to look at?
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